Why are more and more employers doing credit checks?

Why are more and more employers doing credit checks? In jobs I've applied for I will not agree for them to look at my credit it is none of their business and a credit score has nothing to do with ones ability to do a job the right way. Also employers should take into consideration alot of peoples credit score dropped because of the economy. many people lost jobs and were unable to pay credit cards, mortages, car notes etc. I think disqualifying someone from a job because of their credit score is a form of discrimination and no different than not hiring someone because of their skin color, gender, sexual preference etc.